I just ran my weekly 18gal batch of water for tomorrow's water change. My TDS showed 8ppm, up from the usual of 2ppm. I'm not sure if this is indicative of my filter or residue from the tote that I mix my saltwater in. Typically once I've finished the task of changing water I spray the tote out with the sink sprayer and then allow it to air dry upside down. Nonetheless, could it be time to change or flush the membrane on my filter? I have had it for 6 months and have run a total of approximately 500 gallons of water through it. About 6 weeks ago I changed the sediment filter (first one in line). :celeb3:
RO maintenance
- Thread starter Foody
- Start date
iamwrasseman
New member
the ro system is a baby and should last much longer than 500 gallons of water . the prefilter could be plugged up if your incoming water is "dirty" but that is very fast .
Steve Canyon
New member
The membrane should be flushed every time you use it. I do 5 minutes or so at the end of each use and a few minutes before you begin to make water again. Collect a sample in a sterile cup and test before running new makeup water into your collection barrel to avoid contamination. If you're serious about what you're doing, repeat your test at the end of each session.
der_wille_zur_macht
Team RC
IMHO our hobby sometimes over-maintains RO/DI systems. Some of the components people change out every few hundred gallons are rated to 20,000 gallons by the manufacturers (Matrikx CTO Plus carbon blocks for example).
This is my approach these days:
-Change the sediment filter when it looks dirty or every 4 months. They're cheap and really critical to preserving the rest of the system so I don't care if I replace them too often.
-Change the first carbon block at about 5,000 gallons of raw water (which is once a year for me but probably less frequent than that if you have a smaller system)
-Change the second carbon block every 10,000 gallons of raw water (every two years for me)
-Replace the membrane when it's TDS climbs and I can't justify it via any other issue or change in the system or raw water, or at least every two years
-Replace the DI when TDS climbs which ends up being about twice a year for me, or maybe 700 - 800 gallons of product water
This puts me at about half the manufacturer's expected lifetimes for most of these components, which IMHO gives a suitable compromise between having a safety cushion vs wastefulness. When this topic comes up it seems like many people are making less water than me but changing the filters more often, and usually there is no specific justification given - so to me, it sounds wasteful. If you have justification (test results, some known problem in the source water, etc) then so be it.
If you're doing things based on test results, make sure you're testing in a consistent and appropriate manner (i.e. don't test the first cup of water the membrane makes, it'll have a high TDS thanks to creep from water sitting in it. Also, don't put water into a container that is contaminated and then test it).
If you're going to try to do math and replace components based on gallons processed keep in mind the prefilters probably process 4 - 6 times more than your product water volume - so if you make 1000 gallons of RO/DI a year, your prefilters may have seen 6000 gallons through them (since they process the raw water before it's split into product and waste).
This is my approach these days:
-Change the sediment filter when it looks dirty or every 4 months. They're cheap and really critical to preserving the rest of the system so I don't care if I replace them too often.
-Change the first carbon block at about 5,000 gallons of raw water (which is once a year for me but probably less frequent than that if you have a smaller system)
-Change the second carbon block every 10,000 gallons of raw water (every two years for me)
-Replace the membrane when it's TDS climbs and I can't justify it via any other issue or change in the system or raw water, or at least every two years
-Replace the DI when TDS climbs which ends up being about twice a year for me, or maybe 700 - 800 gallons of product water
This puts me at about half the manufacturer's expected lifetimes for most of these components, which IMHO gives a suitable compromise between having a safety cushion vs wastefulness. When this topic comes up it seems like many people are making less water than me but changing the filters more often, and usually there is no specific justification given - so to me, it sounds wasteful. If you have justification (test results, some known problem in the source water, etc) then so be it.
If you're doing things based on test results, make sure you're testing in a consistent and appropriate manner (i.e. don't test the first cup of water the membrane makes, it'll have a high TDS thanks to creep from water sitting in it. Also, don't put water into a container that is contaminated and then test it).
If you're going to try to do math and replace components based on gallons processed keep in mind the prefilters probably process 4 - 6 times more than your product water volume - so if you make 1000 gallons of RO/DI a year, your prefilters may have seen 6000 gallons through them (since they process the raw water before it's split into product and waste).
cardiffgiant
Active member
You can flush debris from the membrane by bypassing the flow restrictor. There are flush kits, or you can make one with 2 john guest tees and a john guest valve.
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Srixon
New member
Best and easiest way to extend membrane life .... And easy to boot!
saltyscotsman
New member
go on line and you can buy a flush kit very easy to install spectra pure sells them
SkiFletch
New member
Yup, my guess is yours just needs a flush. I base my RO membrane solely on TDS testing. Like Steve Canyon, I flush my membrane ALL THE TIME. It "wastes" water, but seeing as how I live within the drainage of the largest freshwater resevoir in the world, I don't much care. It comes from the lake and goes back into it... As for pre-filters, like DWZM I replace my sediment OFTEN. Even though my house has new copper plumbing, living in the city, all the mains are probably cast-iron and that thing catches rust like nobody's business. I replace my 1st carbon every 2 years and 2nd carbon every 4, but then again I have a smaller tank and don't use much water. I've only once in my almost decade of running an RO system replaced the membrane... And that was only after the output was repeatedly higher even after flushes. I probably got the manufacturer's life out of that thing 
cardiffgiant
Active member
Well poop. I bought my RO/DI on ebay and it looks like this: http://www.ebay.com/itm/13058309809...l?_sacat=0&_from=R40&_nkw=130583098099&_rdc=1
I understand that by bypassing the flow restrictor one can "rinse" the membrance with brisk running water, thereby removing deposits on the membrane. I cannot find a flow restrictor anywhere on my system. I've emailed the company that I purchased it from, asking them how to go about it but I fully expect them to prefer to sell expensive membranes rather than educate consumers on how to flush their current membranes. Anyway, if anyone has a model similar to mine and can clue me in, please do. Thank you all.
I understand that by bypassing the flow restrictor one can "rinse" the membrance with brisk running water, thereby removing deposits on the membrane. I cannot find a flow restrictor anywhere on my system. I've emailed the company that I purchased it from, asking them how to go about it but I fully expect them to prefer to sell expensive membranes rather than educate consumers on how to flush their current membranes. Anyway, if anyone has a model similar to mine and can clue me in, please do. Thank you all.
Your flow restrictor may be an in the hose style rather than an in-line. Pull the line just before the inlet to the membrane and look for a small fitting in one end or the other, you've definitely got one somewhere in there!
Examples:
In-Line Style
In-Hose Style
Examples:
In-Line Style
In-Hose Style
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I emailed the company that I purchased the system from. They said the same thing as above. Indeed I do have a small flow restrictor inserted in the drain line coming from the membrane. I was able to remove the line with the restrictor and place a plain line in there and allow it to run for about 30 seconds. I believe that should do it. Thank you all!
